Schwartz (U.S. Pat. Nos. 4,014,604 and 4,102,569) teaches a sound slide having a transparency, a frame with a window for accommodating the transparency, and a sound track carrier on part of the frame. The sound track carrier is coated on opposite sides with layers of magnetic material. One or more pairs of magnetic recording and playback heads are supported by a carrier which is rotatable, linearly displaceable, or both simultaneously so as to scan the magnetic material.
A problem with using magnetic material for recording is its low information storage capacity. A standard two by two inch frame must be enlarged to hold thirty to sixty seconds of speech. To hold more than two minutes of speech is impossible without more than doubling the size of the frame over the standard size.
A further problem is that magnetic recording media is subject to wear. Not only is wear caused by contact with the recording and playback heads, but the media can also be damaged when a number of slides are stacked together or during handling.
In the past, the motion picture industry has employed sound track recording on a 0.1 inch wide strip of the 35 mm film carrying visual images. Sound is usually recorded on film by means of varying the exposure to light corresponding to sound vibrations. Synchronization of sound with pictures allows video images to be accompanied by analog data regarding the images.
An object of the present invention is to provide a means of recording directly on a film slide, sound, control data and digitized visual images to accompany that image either prior to, during, or after exposure forming such image.
Another object of the present invention is to record sound on a medium that is high capacity, so as to be capable of recording for thirty to sixty seconds on a standard two inch by two inch frame.
Another object of the present invention is to provide a medium that does not require contact of the medium with the record, or playback mechanism and is wear resistant.